GM Service Manual Online
For 1990-2009 cars only

Important: The following steps must be completed before using the symptom tables.

  1. Perform the Diagnostic System Check - Lighting Systems before using the Symptom Tables in order to verify that all of the following are true:
  2. • There are no DTCs set.
    • The control module(s) can communicate via the serial data link.
  3. Review the system operation in order to familiarize yourself with the system functions. Refer to Lighting System Operation

Visual/Physical Inspection

    • Inspect for aftermarket devices which could affect the operation of the lighting system. Refer to Checking Aftermarket Accessories in Wiring Systems.
    • Inspect the easily accessible or visible system components for obvious damage or conditions which could cause the symptom.

Intermittent

Faulty electrical connections or wiring may be the cause of intermittent conditions. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.

Symptom List

Refer to a symptom diagnostic procedure from the following list in order to diagnose the symptom:

    •  Backup Lamps Always On
    •  Backup Lamps Inoperative
    •  Cornering Lamps Inoperative
    •  Courtesy Lamps Always On
    •  Courtesy Lamps Inoperative
    •  Courtesy Lamps Inoperative with Headlamp Switch
    •  Courtesy Lamps Inoperative with Doors Open
    •  Courtesy Lamps Inoperative with Unlock of Any Door or Liftgate
    •  Daytime Running Lamps (DRL) Headlamps Always On
    •  Daytime Running Lamps (DRL) Headlamps Inoperative
    •  Fog Lamps Always On
    •  Fog Lamps Inoperative - All
    •  Fog Lamp Indicator Inoperative
    •  Hazard Lamps Inoperative
    •  Headlamps and Park Lamps Inoperative
    •  Headlamps Inoperative - Low Beams
    •  Headlamps Inoperative - Low Beams with Windshield Wipers On
    •  Headlamps - Low Beams On with Headlamp Switch Off
    •  Headlamps Inoperative - Left High Beam
    •  Headlamps Inoperative - Right High Beam
    •  Headlamps Inoperative - High Beams
    •  High Beam On with Headlamp Switch Off
    •  Instrument Panel Compartment Lamp Inoperative
    •  Vanity Mirror Lamp Inoperative
    •  Rear Compartment Lamp Inoperative
    •  Incandescent Lamps Always On
    •  Incandescent Lamps Inoperative
    •  Park Lamps Always On
    •  Park Lamps Inoperative
    •  Stop Lamps Inoperative
    •  Turn Signal Lamps Inoperative
    •  Twilight Sentinel Inoperative
    •  Vacuum Fluorescent Displays Do Not Dim with Instrument Panel Dimmer Switch
    •  Vacuum Fluorescent Displays Inoperative - All
    •  High Beam Indicator Always On
    •  High Beam Indicator Inoperative
    •  LIGHTS ON Indicator Inoperative
    •  Turn Signal Indicator Always On - Left Side
    •  Turn Signal Indicator Always On - Right Side
    •  Turn Signal Indicators Inoperative - Left Side
    •  Turn Signal Indicators Inoperative - Right Side
    •  Turn Signal Lamps Always On - One Side